关键词: 闪电, ENSO, 全球, 相关性, 卫星资料

Abstract:

The spring and winter variabilities of lightning activity and meteorological factors over tropical and subtropical regions on ENSO time scales were investigated based on the satellite flash data and the NCEP/NCAR reanalysis data during 1995-2011. There was an obvious regional difference about the response of lightning to ENSO over tropic and subtropics. Firstly, the regions with lightning increase during El Nino period and decrease during La Nia period were in the Gulf of Mexico, Uruguay, Bengal, southeast China and Sumatra. Secondly, the regions with lightning decrease during El Nino period and increase during La Nina period were in Ecuador, Congo, Mozambique and Madagascar. Thirdly, lightning always increased on ENSO time scales over the Bermuda Islands, east Brazil, west of sub-Saharan Africa and northwest of Australia. Last, lightning always decreased on ENSO time scales over Gulf Coast, south of Saharan, the southwestern foot of the Himalayas Mountain, Indo-China Peninsula, the middle and east of Australia. During El Nino period, holistic correlation between lightning density and ENSO intensity was better than that during La Nina period, and significantly related regions were larger. The obviously positive correlated regions between lightning density and Oceanic Nio Index (ONI) were in the equator and the Southern Hemisphere oceans and coasts during El Nino period, and the negative correlated regions were mostly in the Southern Hemisphere lands during La Nina period. The good correspondence of lightning density anomaly and surface pressure anomaly was a result of close relationship between pressure, atmospheric circulation and local convection activity. Lightning activity had a significant response to surface temperature, and the warming area during El Nino period (the cooling area during La Nina period) had better correlation between lightning density and ONI. Most regions of tropic and subtropics did not have a synchronous lightning and precipitation variation on ENSO time scales, but lightning and precipitation were synchronous over the Pacific and its coast under the influence of El Nino, and over north Indian Ocean and its coast during La Nina period.

Key words: lightning, ENSO, global, correlation, satellite data